Messages in this thread | | | Date | Tue, 22 Mar 2022 20:48:00 +0800 | Subject | Re: [PATCH v3 3/3] arm64/ftrace: Make function graph use ftrace directly | From | Chengming Zhou <> |
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Hello,
ping... have any comments?
Thanks.
On 2022/2/24 5:32 下午, Chengming Zhou wrote: > As we do in commit 0c0593b45c9b ("x86/ftrace: Make function graph > use ftrace directly"), we don't need special hook for graph tracer, > but instead we use graph_ops:func function to install return_hooker. > > Since commit 3b23e4991fb6 ("arm64: implement ftrace with regs") add > implementation for FTRACE_WITH_REGS on arm64, we can easily adopt > the same cleanup on arm64. And this cleanup only changes the > FTRACE_WITH_REGS implementation, so the mcount-based implementation > is unaffected. > > Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> > --- > Changes in v3: > - Add comments in ftrace_graph_func() as suggested by Steve. > > Changes in v2: > - Remove FTRACE_WITH_REGS ftrace_graph_caller asm as suggested by Mark. > --- > arch/arm64/include/asm/ftrace.h | 7 +++++++ > arch/arm64/kernel/entry-ftrace.S | 17 ----------------- > arch/arm64/kernel/ftrace.c | 17 +++++++++++++++++ > 3 files changed, 24 insertions(+), 17 deletions(-) > > diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h > index 1494cfa8639b..dbc45a4157fa 100644 > --- a/arch/arm64/include/asm/ftrace.h > +++ b/arch/arm64/include/asm/ftrace.h > @@ -80,8 +80,15 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) > > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > struct dyn_ftrace; > +struct ftrace_ops; > +struct ftrace_regs; > + > int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); > #define ftrace_init_nop ftrace_init_nop > + > +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > + struct ftrace_ops *op, struct ftrace_regs *fregs); > +#define ftrace_graph_func ftrace_graph_func > #endif > > #define ftrace_return_address(n) return_address(n) > diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S > index e535480a4069..d42a205ef625 100644 > --- a/arch/arm64/kernel/entry-ftrace.S > +++ b/arch/arm64/kernel/entry-ftrace.S > @@ -97,12 +97,6 @@ SYM_CODE_START(ftrace_common) > SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) > bl ftrace_stub > > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER > -SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) // ftrace_graph_caller(); > - nop // If enabled, this will be replaced > - // "b ftrace_graph_caller" > -#endif > - > /* > * At the callsite x0-x8 and x19-x30 were live. Any C code will have preserved > * x19-x29 per the AAPCS, and we created frame records upon entry, so we need > @@ -127,17 +121,6 @@ ftrace_common_return: > ret x9 > SYM_CODE_END(ftrace_common) > > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER > -SYM_CODE_START(ftrace_graph_caller) > - ldr x0, [sp, #S_PC] > - sub x0, x0, #AARCH64_INSN_SIZE // ip (callsite's BL insn) > - add x1, sp, #S_LR // parent_ip (callsite's LR) > - ldr x2, [sp, #PT_REGS_SIZE] // parent fp (callsite's FP) > - bl prepare_ftrace_return > - b ftrace_common_return > -SYM_CODE_END(ftrace_graph_caller) > -#endif > - > #else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > /* > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > index 4506c4a90ac1..35eb7c9b5e53 100644 > --- a/arch/arm64/kernel/ftrace.c > +++ b/arch/arm64/kernel/ftrace.c > @@ -268,6 +268,22 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, > } > > #ifdef CONFIG_DYNAMIC_FTRACE > + > +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > + struct ftrace_ops *op, struct ftrace_regs *fregs) > +{ > + /* > + * Athough graph_ops doesn't have FTRACE_OPS_FL_SAVE_REGS set in flags, > + * regs can't be NULL in DYNAMIC_FTRACE_WITH_REGS. By design, it should > + * be fixed when DYNAMIC_FTRACE_WITH_ARGS is implemented. > + */ > + struct pt_regs *regs = arch_ftrace_get_regs(fregs); > + unsigned long *parent = (unsigned long *)&procedure_link_pointer(regs); > + > + prepare_ftrace_return(ip, parent, frame_pointer(regs)); > +} > +#else > /* > * Turn on/off the call to ftrace_graph_caller() in ftrace_caller() > * depending on @enable. > @@ -297,5 +313,6 @@ int ftrace_disable_ftrace_graph_caller(void) > { > return ftrace_modify_graph_caller(false); > } > +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > #endif /* CONFIG_DYNAMIC_FTRACE */ > #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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